Electric fuel pump



23, 1967 J. E. FELDMAN ELECTRIC FUEL PUMP Filed. Aug. 3, 1965 INVENTOR JOHN E. FELDMAN ATTORNEY INLET United States Patent 3,320,894 ELECTRKC FUEL PUMP John E. Felldnian, Fairfield, 11]., assignor to Airtex Products Division of United Industrial Syndicate, a corporation of New York Filed Aug. 3, 1965, Ser. No. 476,903 4 Claims. (Cl. 103-53) This invention relates to fuel pumps and more particularly to electromagnetically actuated fuel pumps.

It is an object of the invention to provide an electromagnetically actuated fuel pump having an improved switch arrangement.

It is a further object of the invention to provide an electromagnetically actuated fuel pump which will be simple and economical to manufacture and one which will operate reliably with a minimum of maintenance.

Other objects and features of the invention will be apparent from the description which follows:

Briefly, the invention comprises the provision of a solenoid and an armature wherein the armature effects a pump piston carrying the outlet valves of the pump and also carrying a magnetic actuator for a current interrupter which cyclically energizes the solenoid. The piston is provided with spring return effective when the solenoid is deenergized. A particular feature of the invention is an arrangement of magnets having relative motion with respect to each other wherein like poles are so arranged that one magnet can assume either of two stable positions with respect to the other by repulsion force. No intermediate position of the magnets is possible and the repulsion force effects a snap action movement of one magnet with respect to the other which effects a snap action opening and closing of a switch which controls the solenoid.

A detailed description of the invention now follows in conjunction with the appended drawing in which:

FIG. 1 is a plan view of the pump with the central cover plate removed to reveal the interior;

FIG. 2 is a section through 22 of FIG. 1 to a reduced scale; and

FIG. 3 is a section through 33 of FIG. 1 to the same scale.

Referring to the drawing, the pump comprises a casing having twoparts, and 15, which may be threaded together as shown and in which there is an outlet pump chamber 18 and a slidable piston 22 which carries outlet valves, such as 25, preferably in plurality. Thus, there may be two or three such valves, two being shown on FIG. 3. Below the piston is an inlet pump chamber 28 closed by the bottom portion of casing which is machined with a groove to take a solenoid 31. The lower portion of casing component 15 is turned down to form an inlet tube 34 having an inlet valve 37. Above the inlet valve a constricted collar is formed in the casing to effect a seat for the compression spring 38, the upper end of which abuts the piston. The spring is secured and guided at its lower and upper ends in suitable bores of the casing and the piston, as shown.

The casing portion 1t) has a closure wall 42 suitably bored and hushed at 52 to slidably guide a rod 45 having spaced pins 48 at its upper end to coact with a switch arm A. The rod 4-5 carries at its lower end a small cylindrical magnet 54 reciprocally slidable in a brass tube 55 which terminates in a threaded bushing 58 integral therewith that screws into the wall 42.

Accordingly, it will be understood that magnet 54 is sealed from any liquid in chamber 18 and that further seal is provided for rod 45 by means of bushing 52 to ensure no leakage of fuel above wall 42.

Carried by the piston is a ring magnet 65 secured, as by a bolt 68 which clamps magnet 65 against the bottom of a groove 71 machined into the magnet and holds the magnet down securely against the outlet valve housings H. It will be noted that the poles of the magnets are designated by N and S as North and South and that like poles are at the upper and lower ends of the magnets. Accordingly, the magnet 54 has two stable positions with respect to the magnet 65, that is, it can be in the relative position shown in FIG. 3, or in the raised position shown by the phantom lines in FIG. 3.

Above the wall 42 switch arm A is pivoted as by a pin 75 carried by a side plate 78 which is fastened to a block 82 in turn fastened to wall 42 by screws 83. It will, thus, be appreciated that the arm A can rock up and down on pivot 75 carrying a contact 85 engageable with a fixed contact 87 carried on a suitable insulated base 90 and wall 42. Thus, the free extremity of arm A is disposed within notch 93 of block 82 and in moving up and down effects contact engagement and disengagement when actuated by member 48 which passes through it.

The spacing of the pins 48 is such that when rod 45 is lifted, it will effect contact disengagement by abutting arm A, and when the rod is lowered, it will effect contact engagement. It will be understood that arm A is fairly flexible at least at its free extremity for exerting resilient contact pressure when rod 45 moves down. A limit stop screw 98 is carried in block 82.

The arrows shown in FIG. 3 illustrate an obvious electrical circuit from battery 100. The plus side of the battery goes to a binding post 103 carried in an insulating cover plate 106 or can be insulated therefrom in any conventional manner. Plate 106 may be force-fitted in a groove in flange 109 of body portion 10, or otherwise fastened, being held in position by a standpipe 112 which screws into wall 42 as seen in FIG. 2 having a nut 115 which clamps the plate 106 in place. Standpipe 1112 conducts fuel outwardly from chamber 18.

The negative of the battery goes to ground and one end of the solenoid 31 likewise goes to ground, the other end connecting to arm A which by contact 85 and insulated contact 87 can connect to binding post 103 for completion of the circuit for energizing the solenoid.

In operation, the contacts 85 and 87 are initially engaged. This is due to the fact that the spring 38 has moved the piston 22 upwardly at the time the engine was previously stopped. Accordingly, the movement of the magnet 65 upwardly with the piston has forced the magnet 54 downwardly due to interacting fields by repulsion of the north and south poles, whence the contacts are engaged by abutment of the upper pin 98 with the arm. When the ignition switch S is turned on, the solenoid 31 is energized to pull the ferrous piston downwardly. Accordingly, the north poles pass each other and the south poles pass each other, which repels magnet 5 upwardly to effect contact disengagement by abutment of the lower pin 93 with the arm. The movement of the piston downwardly effects a pressure stroke on the fluid in chamber 28 forcing it upwardly through valves 25 into chamber 18. However, contact disengagement deenergizes solenoid 31 and, accordingly, spring 38 moves the piston upwardly again to force fluid in chamber 18 outwardly through the standpipe 112. The upward movement of the piston effects suction through the inlet to open valve 37 for replenishment of fluid in chamber 28. lln this movement, magnet 65 moves up to and slightly beyond magnet 54 causing that magnet to be repelled downwardly once more, thus effecting contact closure to again energize solenoid 31. The action, of course, is repetitive for as long as the ignition switch is turned on.

Electric pumps of the kind described. are normally intended to be immersed in the fuel of the fuel tank. There is, therefore, no vapor lock problem which might other wise occur when a long length of tubing connects the tank to the fuel pump. As in other systems, the fuel rate flow is determined by the carburetor needle valve (not shown). The action of the mutually repelling magnets provides for snap opening and closing of the contacts, thereby eliminating arcing while at the same time effecting sufficient contact pressure.

I claim:

1. An electric pump comprising a housing having an intake chamber and an outlet chamber and valves for respective chambers, a solenoid in said housing, a piston comprised of magnetic material so as to be attracted to said solenoid when energized, a spring for normally biasing said piston away from said solenoid, a first magnet carried by said piston and polarized in a direction axially of said piston, a second magnet carried by said housing, and contact means actuatable by said second magnet, said second magnet being polarized in a direction axially of said piston, like poles of said magnets being at the same ends thereof, whereby movement of said first magnet effects repulsion in an opposite direction of said second magnet for effecting snap opening and closing of said contacts, said contacts being operative to energize said solenoid when engaged and to deenergize said solenoid when disengaged whereby repetitive reciprocation of said piston is effected.

2. An electric pump comprising a housing having a piston therein, said housing having an inlet chamber at one side of said piston and an outlet chamber at the other side of said piston, outlet valve means carried by said piston, a solenoid disposed in said inlet chamber, said piston being comprised of magnetic material so as to be attracted to said solenoid when said solenoid is energized, inlet valve means disposed to permit influx of fluid to said inlet chamber, a first magnet carried by said piston in said outlet chamber, a second magnet disposed adjacent said first magnet, the poles of said magnets being aligned to effect repulsion snap action movement of said second magnet upon movement of said first magnet with said piston, contact means actuatable by movement of said second magnet and operative to control current to said solenoid to repetitively energize and deenergize said solenoid by effecting reciprocation of said piston responsive to said energization and deenergization.

3. An electric pump comprising a housing having a piston therein, said housing having an inlet chamber at one side of said piston and an outlet chamber at the other side of said piston, outlet valve means carried by said piston, a solenoid disposed in said inlet chamber, said piston being comprised of magnetic material so as to be attracted to said solenoid when said solenoid is energized, inlet valve means disposed to permit influx of fiuid to said inlet chamber, a first magnet carried by said piston in said outlet chamber, a second magnet disposed adjacent said first magnet, the poles of said magnets being aligned to effect movement of said second magnet upon movement of said first magnet with said piston, contact means actuatable by movement of said second magnet and operative to control current to said solenoid to repetitively energize and deenergize said solenoid by effecting reciprocation of said piston responsive to said energization and deenergization, said first magnet comprising a ring having a bore, said second magnet comprising a plug disposable within said bore, means for slidably guiding said second magnet and means intermediate said magnets for sealing said second magnet from tfluid in said outlet chamber.

4. An electric pump comprising a housing having a piston movable therein, solenoid means for efiecting movement of said piston in one direction and spring means for moving said piston in the opposite direction, means for energizing and deenergizing said solenoid comprising actuatable contact elements and means for eiTecting snap action relative movement of said contact elements comprising a pair of magnets disposed so as to have interactin g repulsion magnetic fields, one such magnet being movable by said piston and the other such magnet being operatively connected to said contact elements, whereby movement of said one such magnet effects movement of the other such magnet by magnetic force. 7

References Cited by the Examiner- UNITED STATES PATENTS 2,481,147 9/1949 Parker et al 3l0-l8 FOREIGN PATENTS 593,400 3/1960 Canada.

References Cited by the Applicant ROBERT M. WALKER, Primary Examiner. 

1. AN ELECTRIC PUMP COMPRISING A HOUSING HAVING AN INTAKE CHAMBER AND AN OUTLET CHAMBER AND VALVES FOR RESPECTIVE CHAMBERS, A SOLENOID IN SAID HOUSING, A PISTON COMPRISED OF MAGNETIC MATERIAL SO AS TO BE ATTRACTED TO SAID SOLENOID WHEN ENERGIZED, A SPRING FOR NORMALLY BIASING SAID PISTON AWAY FROM SAID SOLENOID, A FIRST MAGNET CARRIED BY SAID PISTON AND POLARIZED IN A DIRECTION AXIALLY OF SAID PISTON, A SECOND MAGNET CARRIED BY SAID HOUSING, AND CONTACT MEANS ACTUATABLE BY SAID SECOND MAGNET, SAID SECOND MAGNET BEING POLARIZED IN A DIRECTION AXIALLY OF SAID PISTON, LIKE POLES OF SAID MAGNETS BEING AT THE SAME ENDS THEREOF, WHEREBY MOVEMENT OF SAID FIRST MAGNET EFFECTS REPULSION IN AN OPPOSITE DIRECTION OF SAID SECOND MAGNET FOR EFFECTING SNAP OPENING AND CLOSING OF SAID CONTACTS, SAID CONTACTS BEING OPERATIVE TO ENERGIZE SAID SOLENOID WHEN ENGAGED AND TO DEENERGIZE SAID SOLENOID WHEN DISENGAGED WHEREBY REPETITIVE RECIPROCATION OF SAID PISTON IS EFFECTED. 